Lens systems comprising plastic and liquid lens elements

Abstract

Lens triplets (two achromats and a apochromat) are disclosed that are well-corrected for chromatic aberration and for spherochromatism. Each triplet comprises two identical acrylic lens elements and a liquid lens element.

I claim: 
     
       1. A lens system comprising two plastic lens elements and a liquid lens element disposed coaxially along an optic axis, said two plastic lens elements being substantially identical to each other, said two plastic lens elements and said liquid lens element coacting with each other to provide a common back focal distance for said lens system at at least three discrete wavelengths. 
     
     
       2. A lens system comprising two plastic lens elements and a liquid lens element disposed coaxially along an optic axis, said two plastic lens elements being substantially identical to each other, said two plastic lens elements and said liquid lens element coacting with each other to focus optical radiation at three discrete wavelengths passing through said lens system onto a common focal surface. 
     
     
       3. A lens system comprising two plastic lens elements and a liquid lens element disposed coaxially along an optic axis, said two plastic lens elements being substantially identical to each other, said two plastic lens elements and said liquid lens element coacting with each other to focus optical radiation at two discrete wavelengths passing through said lens system onto a common focal surface with a change in focus of less than one-quarter wavelength over a range of wavelengths between said two discrete wavelengths, said two discrete wavelengths at which said optical radiation is focussed onto said focal surface having a spectral separation of at least about 0.07 micron. 
     
     
       4. The lens system of claim 3 wherein said two plastic lens elements are made of acrylic. 
     
     
       5. The lens system of claim 4 wherein said liquid lens element is made of an optical liquid having an index of refraction of approximately 1.71035 at a wavelength of 0.58756 micron and an Abbe number of approximately 20.95. 
     
     
       6. The lens system of claim 4 wherein said liquid lens element is made of an optical liquid having an index of refraction of approximately 1.50012 at a wavelength of 0.58756 micron and an Abbe number of approximately 35.31. 
     
     
       7. The lens system of claim 4 wherein said liquid lens element is made of an optical liquid having an index of refraction of approximately 1.47011 at a wavelength of 0.58756 micron and an Abbe member of approximately 38,08. 
     
     
       8. The lens system of claim 3 wherein said plastic lens elements and said liquid lens element are configured and positioned along said optic axis substantially according to an optical prescription as follows:   ______________________________________                                    
Surface                                                                   
       Radius     Thickness                                               
No.    (inches)   (inches)  N.sub.d                                       
                                  V.sub.d                                 
                                       Material                           
______________________________________                                    
1        8.36182  0.07106   1.49176                                       
                                  57.46                                   
                                       acrylic                            
2      -25.11101  0.00142   1.71035                                       
                                  20.95                                   
                                       710209                             
3       25.11101  0.07106   1.49176                                       
                                  57.46                                   
                                       acrylic                            
4       -8.36182  9.92095                                                 
5      (image plane)                                                      
______________________________________                                    
     
     
     
       9. The lens system of claim 3 wherein said plastic lens elements and said liquid lens element are configured and positioned along said optic axis substantially according to an optical prescription as follows:   ______________________________________                                    
Surface                                                                   
       Radius     Thickness                                               
No.    (inches)   (inches)  N.sub.d                                       
                                  V.sub.d                                 
                                       Material                           
______________________________________                                    
1       9.55933   0.07106   1.49176                                       
                                  57.46                                   
                                       acrylic                            
2      -6.31572   0.00142   1.50012                                       
                                  35.31                                   
                                       499352                             
3       6.31572   0.07106   1.49176                                       
                                  57.46                                   
                                       acrylic                            
4      -9.55933   9.92323                                                 
5      (image plane)                                                      
______________________________________                                    
     
     
     
       10. The lens system of claim 3 wherein said plastic lens elements and said liquid lens element are configured and positioned along said optic axis substantially according to an optical prescription as follows:   ______________________________________                                    
Surface                                                                   
       Radius     Thickness                                               
No.    (inches)   (inches)  N.sub.d                                       
                                  V.sub.d                                 
                                       Material                           
______________________________________                                    
1       10.78748  0.07106   1.49176                                       
                                  57.46                                   
                                       acrylic                            
2       -4.77688  0.00142   1.47011                                       
                                  38.08                                   
                                       470380                             
3        4.77688  0.07106   1.49176                                       
                                  57.46                                   
                                       acrylic                            
4      -10.78748  9.92072                                                 
5      (image plane)                                                      
______________________________________